A unified comparative study on the classical lamination theory, hole drilling, slitting, and curvature measurement methods for assessment of residual stress in laminated polymeric composites

Abstract

Residual stresses are balanced, non-uniform, undesirable, and often harmful in laminated polymer composite materials. Different methods are developed to measure these stresses in composites. In this manuscript, three experimental measurement methods, namely ‘hole drilling’, ‘slitting’, and ‘curvature’ methods, are considered, and the results are compared with those of classical lamination theory (CLT). It is demonstrated that the hole drilling technique can be used to measure residual stress in the near-surface areas of the structures, while the slitting method is often employed to assess residual stresses through the depth of specimens. Moreover, the curvature method shows great potential for estimating the overall residual stress quality in laminated composites with un-symmetrical configurations.